following questions, one from medicine and onefrom taxation:A 32-year-old woman with type 1 diabetes mellitus hashad progressive renal failure. Her hemoglobin con-centration is 9 g/dL. A blood smear shows nor-mochromic, normocytic cells. What is the problem?

I inherited real-estate from a relative who died 5 years
ago via a trust that was created before his death. The
property was sold this year after dissolution of the
trust, and the money was put in a Roth-IRA. Which
tax form(s) do I need to file?

We will call these types of questions scenario-basedquestions. In these types of questions, it is not gener-ally the case that the answer and supporting evidencecan be contained in one document. Rather, for manyscenario-based questions, information from multipledocuments and other sources must generally beretrieved and then integrated to answer the questionsproperly. Furthermore, we must often apply generalknowledge to a specific case, as in a medical scenarioabout a patient.

Before beginning work on automated scenario-based question answering, we investigated how
humans solve such questions. We asked domain
experts to describe their approach to solving a set of
scenario-based questions in the medical domain. An
example is shown in figure 1. Many drew a graph of
initial signs and symptoms leading to their most likely possible causes and connecting them to a final
conclusion. This motivated us to look into graph-based methods as a way of answering scenario-based
questions automatically.

In this article, we describe WatsonPaths, a system
that builds on Watson to answer scenario-based questions. The core idea is to break the question down
into parts, over which we can ask and answer factoid
subquestions using Watson, then integrate these
answers into a graphic model that can be used to

Figure 1. A Simple Diagnosis Graph for a Patient with Erythropoietin Defciency.

“A 32-year-old woman with type 1 diabetes mellitus has had progressive renal failure... Her hemoglobinconcentration is 9 g/dL... A blood smear shows normochromic, normocytic cells. What is the problem?